1. Field of the Invention
The present invention relates to a coin discrimination apparatus and more particularly, to a coin discrimination apparatus that makes it possible to discriminate the denomination and authenticity of coins accurately even if they are bimetallic coins.
The term “coin” used in this specification means widely coins as a currency, tokens, medals, and so on, which may have any shape such as circular and polygonal ones.
2. Description of Related Art
Conventionally, as a prior art, a coin denomination discrimination apparatus is known, as disclosed, for example, in the Japanese Patent No. 4780494 (see FIGS. 2 to 6 and Paragraphs 0026 to 0040). This apparatus comprises a slide base made of a non-magnetic material, a rotator made of a non-magnetic material and formed adjacent to the slide base in such a way as to be rotated in a plane parallel to the slide base, a reference guide formed outside a rotation path of the rotator, and a magnetic sensing device for discriminating the denomination of coins provided near a coin carrying path through which coins are carried by rotation of the rotator.
The magnetic sensing device includes a diameter sensor, a material sensor, and a thickness sensor.
With the prior-art coin denomination discrimination apparatus disclosed in the Japanese Patent No. 4780494, the denomination of target coins is discriminated using one material sensor, one thickness sensor, and three diameter sensors serving as the magnetic sensing device. The material sensor and the thickness sensor are arranged in such a way as to be opposed to not only the central portion of a coin but also the peripheral part thereof.
When discriminating the denomination of a bimetallic coin, where the peripheral part (ring-shaped part) and the central part (i.e., core part) are made of different metals, the data about the materials of the core and ring-shaped parts of the bimetallic coin is obtained by the material sensor and the data about the material of the connection portion of the core and ring-shaped parts thereof is obtained by the same material sensor. Similarly, the data about the thicknesses of the core and ring-shaped parts is obtained by the thickness sensor and the data about the thickness of the connection portion is obtained by the same thickness sensor. Because the connecting portion contains some structural unevenness, the data obtained from the connecting portion is likely to include dispersion or variations. Accordingly, the data obtained from the connecting portion by the material sensor and the data obtained from the connecting portion by the thickness sensor also will include dispersion or variations, which raises a problem of degradation in discrimination accuracy of bimetallic coins.